A cycloolefin polymer obtained by polymerizing a polymerizable monomer including a cycloolefin monomer (e.g., norbornene-based monomer) in the presence of a metathesis polymerization catalyst exhibits excellent electrical properties, mechanical properties, impact resistance, heat resistance, weatherability, and the like. Therefore, the cycloolefin polymer has attracted attention as a resin material for forming a formed article used in various fields.
When using the cycloolefin polymer as a resin material, a filler such as a glass reinforcement material may be added to improve various properties (e.g., rigidity). However, the cycloolefin polymer has very low polarity, and exhibits poor adhesion to the filler.
In order to improve adhesion between the cycloolefin polymer and the filler, the surface of the filler may be treated in advance using a coupling agent or the like. For example, Patent Document 1 discloses a polymerizable composition that includes a magnetic material and bulk-polymerizable monomer, wherein the surface of the magnetic material has been treated with a silane coupling agent or the like.
However, since it is necessary to treat the surface of the filler in advance, the operation is complex. Moreover, a resin formed article that exhibits the desired heat resistance and impact resistance may not be obtained even when using such a surface-treated filler.